Advances in monitoring technology allow blood pressure waveforms to be collected at sampling frequencies of 250–1000 Hz for long time periods. However, much of the raw data are under-analysed. Heart rate variability (HRV) methods, in which beat-to-beat interval lengths are extracted and analysed, have been extensively studied. However, this approach discards the majority of the raw data. Objective: Our aim is to detect changes in the shape of the waveform in long streams of blood pressure data. Approach: Our approach involves extracting key features from large complex data sets by generating a reconstructed attractor in a three-dimensional phase space using delay coordinates from a window of the entire raw waveform data. The naturally occurring baseline variation is removed by projecting the attractor onto a plane from which new quantitative measures are obtained. The time window is moved through the data to give a collection of signals which relate to various aspects of the waveform shape. Main results: This approach enables visualisation and quantification of changes in the waveform shape and has been applied to blood pressure data collected from conscious unrestrained mice and to human blood pressure data. The interpretation of the attractor measures is aided by the analysis of simple artificial waveforms. Significance: We have developed and analysed a new method for analysing blood pressure data that uses all of the waveform data and hence can detect changes in the waveform shape that HRV methods cannot, which is confirmed with an example, and hence our method goes ‘beyond HRV’.
Background and ObjectiveThe inhibition of fatty acid amide hydrolase 1 (FAAH) has been proposed as a novel mechanism for treating pain syndromes by increasing the levels of endogenous cannabinoids (ECs). This study describes the safety, tolerability, pharmacokinetics and pharmacodynamics of V158866, a reversible FAAH inhibitor, after first administration to man.Methods51 healthy male subjects were recruited into this double-blind, randomised, placebo-controlled, adaptive dose, phase I single (Part A) and repeated ascending dose (Part B) study. The primary outcome was the safety and tolerability of V158866. Secondary outcomes were (1) pharmacokinetics of V158866 and (2) pharmacodynamics of V158866, as assessed by changes in plasma EC concentrations.ResultsSingle oral doses of 5–300 mg and repeated oral doses of 50–500 mg were evaluated. V158866 was well tolerated, with no apparent treatment-related effects on laboratory variables. V158866 was rapidly absorbed with a mean terminal elimination half-life of 9.6–18.3 h (Day 7; Part B). V158866 reached steady state within 2–3 days of administration, with an accumulation ratio, based on AUC0–24h, of approximately 2 on Day 7. V158866 showed a linear relationship between dose and AUC across the entire dose range. V158866 caused reversible, dose-related increases in plasma ECs. At hemi-equilibrium, there was a sigmoidal maximum effect relationship between plasma V158866 concentrations and changes in plasma ECs.ConclusionsV158866 is well tolerated, with linear pharmacokinetics suitable for once-daily administration, and reversible effects on plasma ECs. Maximum increases in plasma ECs occur with V158866 doses of 300–500 mg/day.Electronic supplementary materialThe online version of this article (doi:10.1007/s40268-016-0127-y) contains supplementary material, which is available to authorized users.
2+ ] i elevation but the e ects of UTP (E max of IL-8 response increased to 50+1% of the maximal response to ATP, pEC 50 increased to 9.8+0.1) were greater than those of 2MeSADP (E max increased to 36+2%, pEC 50 increased to 8.7+0.2). 5 The potentiation of IL-8-mediated Ca 2+ signalling by UTP was not dependent upon the time of IL-8 addition following UTP but was dependent on the continued presence of UTP. Potentiated IL-8 Ca 2+ signalling was apparent in the absence of extracellular Ca 2+ , demonstrating the release of Ca 2+ from intracellular stores. 6 Activation of P2Y1 and P2Y2 receptors also revealed Ca 2+ signalling by an endogenously expressed, Ga s -coupled b-adrenoceptor. 7 In conclusion, pre-stimulation of P2Y nucleotide receptors, particularly P2Y2, facilitates Ca 2+ signalling by either recombinant CXCR2 or endogenous b-adrenoceptors.
Chk1 kinase is a critical component of the DNA damage response checkpoint especially in cancer cells and targeting Chk1 is a potential therapeutic opportunity for potentiating the anti-tumor activity of DNA damaging chemotherapy drugs. Fragment elaboration by structure guided design was utilized to identify and develop a novel series of Chk1 inhibitors culminating in the identification of V158411, a potent ATPcompetitive inhibitor of the Chk1 and Chk2 kinases. V158411 abrogated gemcitabine and camptothecin induced cell cycle checkpoints, resulting in the expected modulation of cell cycle proteins and increased cell death in cancer cells. V158411 potentiated the cytotoxicity of gemcitabine, cisplatin, SN38 and camptothecin in a variety of p53 deficient human tumor cell lines in vitro, p53 proficient cells were unaffected. In nude mice, V158411 showed minimal toxicity as a single agent and in combination with irinotecan. In tumor bearing animals, V158411 was detected at high levels in the tumor with a long elimination half-life; no pharmacologically significant in vivo drug-drug interactions with irinotecan were identified through analysis of the pharmacokinetic profiles. V158411 potentiated the anti-tumor activity of irinotecan in a variety of human colon tumor xenograft models without additional systemic toxicity. These results demonstrate the opportunity for combining V158411 with standard of care chemotherapeutic agents to potentiate the therapeutic efficacy of these agents without increasing their toxicity to normal cells. Thus, V158411 would warrant further clinical evaluation.
Background and purpose: Pharmacokinetic/pharmacodynamic (PK/PD) models are necessary to relate the degree of drug exposure in vivo to target blockade and pharmacological efficacy. This manuscript describes a murine agonist-induced CXCR3 receptor internalization assay and demonstrates its utility for PK/PD analyses. Experimental approach: Activated murine DO11.10 cells were incubated with agonist in the presence or absence of a CXCR3 antagonist and changes in surface CXCR3 expression were detected by flow cytometry. For PK/PD analysis, mice were dosed with a small molecule CXCR3 antagonist, NBI-74330, (100 mg kg À1 ) orally or subcutaneously and plasma samples taken at specified timepoints for the CXCR3 internalization assay. Key results: Surface CXCR3 expression was specifically decreased in response to CXCL9, CXCL10 and CXCL11. CXCL11 was the most potent CXCR3 agonist in buffer (pA 50 ¼ 9.23±0.26) and the pA 50 for CXCL11 was unaltered in murine plasma (pA 50 ¼ 9.17 ± 0.15). The affinity of a small molecule CXCR3 antagonist, NBI-74330, was obtained in the absence or presence of plasma (buffer pA 2 value: 7.84±0.14; plasma pK B value 6.36±0.01). Administration of NBI-74330 to mice resulted in the formation of an N-oxide metabolite, also an antagonist of CXCR3. Both antagonists were detectable up to 7 h post oral dose and 24 h post subcutaneous dose. Measurement of CXCR3 internalization demonstrated significant antagonism of this response ex vivo, 24 h following subcutaneous administration of NBI-74330. Conclusions and implications: The CXCR3 receptor internalization assay provides a robust method for determining agonist potency orders, antagonist affinity estimates and PK/PD analyses, which discriminate between dosing regimens for the CXCR3 antagonist NBI-74330.
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